Nickel Alloy-Alloy 201

At higher temperatures Nickel 201 plate should be utilized. Both grades are approved under ASME Boiler and Pressure Vessel Code Section VIII, Division 1. Nickel 200 plate is approved for service up to 600ºF (315ºC), while Nickel 201 plate is approved up to 1250ºF (677ºC).
Corrosion Resistance
Nickel 200 and 201 plate possess excellent resistance in many corrosive environments including hydrofluoric acid and alkalis. These alloys perform extremely well under reducing conditions but can also be used in oxidizing conditions due to the formation of a passive oxide film. The outstanding resistance of Nickel 200 and 201 plate in caustics is based on this type of protection.

In conditions where temperatures exceed 600ºF (315ºC), Nickel 201 plate is the preferred material, due to its lower carbon content.

The resistance of Nickel 200 and 201 plate in mineral acid applications varies depending on the concentration and temperature, as well as if the solution is aerated. The alloys perform better in non-aerated acid solutions.

Nickel 200 and 201 plate perform well in acids, alkalis, and neutral salt solutions. However, in oxidizing salt solutions, strong corrosion can take place.

Both alloys resist dry gases at room temperatures. Nickel 201 plate can be used in hydrogen chloride and dry chlorine gas up to 1022ºF (550ºC).
Fabrication Data
Nickel 200 and 201 plate can be easily welded and processed by standard shop fabrication practices.

Hot Forming
Hot bending operations should be performed in the temperature range of 1600º to 2250ºF (870º to 1230ºC). In any operation, care should be taken to avoid heating Nickel 200 and 201 plate above the upper temperature limit of 2250ºF (1230ºC).

Cold Forming
Nickel 200 and 201 can be worked by any conventional cold-forming method. The forming characteristics are comparable to those of mild steel; however, because of the higher elastic limits of Nickel 200 and 201, greater power will be needed to perform the operations. Severe forming can be done manually but will require intermediate anneals to restore the alloy’s softness.

Machining
Nickel 200 and 201 plate should be machined in the annealed condition whenever possible. These grades have the propensity to work harden, making it necessary to utilize low cutting speeds and requiring the cutting tool to stay engaged at all times. An adequate chip depth is important in order to avoid contact with the previously formed work-hardened zone. Liquid cold forming lubricants should be utilized to assure optimal heat dissipation.

Welding
Nickel 200 and 201 plate can be joined by a variety of welding procedures including inert gas and resistance welding. Welding practices are similar to those used to join austenitic stainless steels. Neither preheating nor post-weld heat treatments are usually required.